He'd said, maybe as a joke, that "I will NEVER use a walker, but I will accept a lacquered black stick topped with a silver, ruby-eyed Death's head. This will be brandished at whippersnappers, with an admonishment to Get Off My Damn Lawn™."
Which made the gift easy. They got him exactly what he asked for, and then some. This walking stick has an amazing top featuring the likness of Myth's Soulblighter, something that'll bring one hell of a smile to the face of old-time PC gamers (the Myth games were what Bungie worked on after Marathon and before Halo), but in addition, it's got a concealed sword in it as well.
So not only does he have a Bungie-themed walking stick, he can pretend to be Rutger Hauer in Blind Fury while he's at it.